WHAT'S UP DOC? Precision medicine

Tuesday

May 16, 2017 at 4:30 PMMay 16, 2017 at 4:30 PM

By Dr. Jeff Hersh/Daily News Correspondent

Q: What is precision medicine?

A: It is great news that improvements in the treatment for ALL (acute lymphocytic leukemia) have increased the five-year (or longer) survival rate for children (birth to 19 years old) from 80 percent in 1990 to over 90 percent now. But what is different about the 10 percent that still do not respond to these treatments? Is their disease different? Are they different?

Per the National Institutes of Health, precision medicine (also called personalized medicine) is “an emerging approach for disease treatment and prevention that takes into account individual variability in genes, environment and lifestyle for each person.” The concept of precision medicine is not a new one. For example, different blood types and markers have been known since 1900, and transfusions have been ‘personalized’ to try to minimize adverse reactions by matching donors to recipients.

Medicine has already taken many steps toward a more precision-medicine-based approach. For example, many markers on cancer cells have been identified that allow more patient-centric treatments. It is also now possible to evaluate a patient’s genetic markers to help guide therapy for many other diseases; for example, the selection of which medication is likely to be effective in a given patient with depression may be guided by an analysis of their genome, and in this way the patient may achieve benefit sooner, while avoiding unnecessary toxicity from less effective treatments, as well as minimizing costs by not wasting money on ineffective treatments.

The next steps in a precision medicine approach will start with techniques to gain an even deeper understanding of an individual patient’s genome (the genetic map that gives specific recipes of how their cells function), epigenome (all the chemical compounds and signals that guide the specific selection of which recipes the cells should follow at any given moment), proteome (the specific protein results made as a result of these recipes), as well as other aspects specific to the patient. In addition, a similar deep analysis may be done on diseased cells, for example cancer cells that have developed in the patient.

The rapid improvement in understanding and technology in the fields of genetics, molecular biology, and many other areas have set the stage for precision medicine to move forward. An example of this rapid improvement is the advances made in sequencing an individual person’s genetic makeup. The human genome project was the research that first mapped out the entire genetic code of a human. It cost 2.7 billion dollars and took from 1990, when the project was begun, to 2003, when the project was completed. Today a person’s entire genome can be mapped in about three days or less, at a cost of several thousand dollars. This promises to get even better over the next several years, with projections to be able to do this in under a day, at a cost of just several hundred dollars.

Further advances in precision medicine will help guide decisions on what screening tests, diagnostic tests and treatments are best for an individual patient. These advances will also enable the design of individualized treatment options for a patient, for example by guiding their own immune system to aggressively attack their cancer, increasing efficacy while minimizing complications. This patient-centric and patient-focused approach may also help cut costs by avoiding the expense of treating complications and giving unnecessary/ineffective tests/treatments.

There are some potential problems that may arise with a precision medicine approach. Even as techniques and evaluations improve, they will not be perfect. Misinterpretation of results, imperfections in the testing (in terms of reliability and reproducibility), variations from patient to patient and within a given patient over time (possibly due to complex interactions of the many variables and factors within a given patient), changing environmental factors, and many other factors can limit the application of personalized medicine approaches. In addition, the huge amount of data generated by personalized medicine will need better information technology approaches to interpret and utilize it to its full potential.

These issues are being addressed, and precision medicine is rapidly moving forward. Because of this the future of medicine holds great promise, and hopefully someday soon we will treat each patient like the individual they are, identifying what is best for them by identifying/designing specific treatments, diagnostic tests and screening tests to improve their quality and quantity of life.